JPH0223961A - Laminated rubber plug for medicine, method and mold for preparing the same - Google Patents

Abstract

PURPOSE:To make the close adhesiveness of a rubber plug and the mouth of a container more perfect by providing a cutting edge to the circumferential part of the rubber plug leg part of a lower mold and cutting the excessive film of the fluororesin laminated during the molding of the rubber plug under pressure and heating to laminate the film only to a leg part. CONSTITUTION:A fluororesin film 22 is placed on a lower mold 3 having an edge 8 formed to the periphery of the upper end thereof and, next, a middle mold 2 is superposed on said film 22 and a sheet like rubber material 10 is further placed thereon and, at last, an upper mold 1 is superposed and the whole is introduced into a compression molding press machine to be heated under pressure. After molding and vulcanization are completed, the mold is drawn out from the press machine and, when the upper mold 1 is opened, a molded product is adhered to the upper mold 1. At this time, the film 2 is already cut between the cutting edge 8 provided to the lower mold 3 and the under surface 9 of the middle mold 2 and the fluororesin film 21 is perfectly integrated with the leg part 20b of the molded product 20 to be eliminated thereto and it is unnecessary to perform finish at all. The molded product is detached from the upper mold 1 and the middle mold 2 is further detached to remove the fluororesin film remaining on the lower mold 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vulcanization mold for producing rubber stoppers for pharmaceutical use, particularly rubber stoppers laminated with fluororesin films for use in medical containers.

[Prior art] In recent years, demands for reliability have increased for pharmaceutical containers, and volatile substances in the rubber stopper elute from the rubber stopper into the drug, and volatile substances in the rubber stopper may come out from the rubber stopper regardless of their impact on the drug. It is desired that the amount of the substance be extremely reduced or not detected at all, and it is expected that this will become even more severe in the future.

By the way, in the case of injectable drugs, considering that a needle is used to inject the drug into the human body, animals, etc., the rubber stopper into which the needle is inserted needs to have resilience to prevent leakage.

Rubber is used as a suitable material because of its advantages such as better resilience than other polymers, low moisture permeability and water absorption depending on the type of rubber, excellent moldability, and low price. However, since rubber stoppers have the problem of elution mentioned above,
There is a need to solve this problem, and as a countermeasure, it has been proposed, for example, to laminate a fluororesin film that is inert and has excellent chemical resistance to the liquid-contacted part of the rubber stopper. For example, Special Publication No. 52-1355, Special Publication No. 54-911
No. 9, Japanese Patent Publication No. 57-47637, Special Publication No. 57-531
No. 84, JP-A-59-5048, JP-A-61-476
No. 37, JP-A No. 277445, JP-A No. 62-
No. 176450 and others have proposed the laminate rubber stopper shown in FIGS. 6(a) and 6(b).

These known manufacturing methods can be categorized as follows: (1) Production in which a fluororesin film is molded into a plug shape, placed in a lower mold, and compounded rubber is press-fitted inside, followed by vulcanization molding by applying pressure and heating. Law.

(2) Vulcanize and mold only the legs of the rubber stopper shape using an unvulcanized rubber sheet and resin film in the first mold, and then mold first onto the legs of the second mold that has the entire rubber stopper shape. A manufacturing method in which the film-laminated legs are fitted, a vulcanized rubber sheet is placed on top, and vulcanization is formed by applying pressure and heating.

(3) A manufacturing method in which a film is placed on a lower mold, an unvulcanized rubber sheet is placed on top of it, an upper mold is placed, and the film is vulcanized and molded by applying pressure and heating.

(4) Molding the fluororesin film into a plug shape, leaving a part of the flange and cutting it into main legs, place it on the lower mold, cover it with the upper mold, and then pour the rubber through the injection hole provided in the upper mold. A manufacturing method that involves injecting and heating under pressure to vulcanize and mold.

It can be divided into

Among these manufacturing methods, (1), (2), and (4) are classified as two-stage molding methods, and (3) is classified as one-stage molding method. The parts laminated with film by these methods are the entire surface of the legs and flanges in (1) and (3), and parts of the legs and flanges in (2) and (4). However, in method 4), a film formed into a plug shape and cut is simply placed in a rubber plug mold, so there is a problem that the rubber wraps around the bottom surface of the film during pressurization and heating.

By the way, if the flange of the rubber stopper is not in perfect contact with the top surface of the container mouth, even if the stopper is sealed, air and moisture will not be able to completely prevent the intrusion of air and moisture from the outside. There is a risk of deterioration or contamination. Therefore, it is preferable that the rubber material of the flange portion be exposed. Incidentally, in the case of (2) above, the leg portion is also cut at a location close to the leg portion of the flange portion.

In the case of (3), it is a one-step molding method that requires fewer steps and is advantageous in terms of manufacturing cost, but the rubber stopper can only be applied when the ratio of the length of the leg to the outer diameter of the leg is the same or short. Furthermore, when molding under pressure and heat, unless the fluororesin film can be stretched to a large extent, it will tear and the purpose of lamination will not be achieved and the product will not be produced, and the shapes of rubber plugs that can be used are limited.

[Problems to be Solved by the Invention] The present invention has been made in order to solve the problems of the prior art as described above and provide an excellent laminate rubber stopper. To provide a laminated rubber stopper in which the laminated portion is confined only to the legs of the rubber stopper in order to achieve more complete contact with the mouth.

Another object of the present invention is to provide a method for manufacturing such a laminated rubber stopper in a simple manner.

Still another object of the present invention is to provide a mold for use in the above method.

[Means for solving the problem] In order to achieve the object, the inventors of the present invention made various studies and found that the molds were stacked in three layers (upper, middle, and lower), and a cutout was formed around the rubber stopper leg of the lower mold. By attaching an edge, applying pressure, and heating to cut off the excess film of fluororesin laminated during rubber stopper molding, we have completed a method that allows rubber stoppers with only the legs laminated to be molded in one step.

The laminate rubber stopper according to the present invention for achieving the above object is characterized by a rubber stopper for closing the bottle opening of a medicine sealing bottle, which has a flange that is tightly attached to the upper surface around the bottle opening. and a leg that is inserted into the bottle mouth from the bottom of the main body, with a circumferential boundary line in the vicinity of the base of the leg that extends downward at a generally right angle from the bottom of the flange. The entire surface of the legs is laminated with a fluororesin film.

In addition, as a method for manufacturing such a rubber stopper, a fluororesin film for lamination is placed on a lower mold having a cavity that roughly matches the shape of the leg, and a thin medium mold having a cavity that matches the outer peripheral shape of the base of the leg is used. is placed on the fluororesin film placed above, and an appropriate amount of the rubber material constituting the rubber stopper body is placed in the cavity formed by the medium mold, so that the rubber stopper has a cavity that matches the shape of the rubber stopper body. A method of molding a rubber stopper by applying an upper mold and applying pressure and heating, the method comprising providing an edge for cutting the film at the upper edge of the cavity of the lower mold, and gradually increasing the pressure during the molding. This is another feature of the present invention.

Further, the present invention has yet another feature of the mold having the above-described structure used in the above-described method.

In the present invention, the position of the circumferential boundary line of the laminate with respect to the legs of the rubber stopper is determined by the thickness of the medium, and from the desire to reduce the elution of volatile substances from the rubber material as much as possible. It is desirable that the legs be as close as possible to the root part where the legs intersect with the flange, but if they are too close, the middle mold may become thinner and the mechanical strength of the middle mold during molding may be insufficient. It is best to take this into consideration when deciding. When using general mold steel, the OJ is usually ~2.0 mm, preferably 0.5 ~
1.5 mm, particularly preferably about 0.5 mm in the case of a common vial rubber stopper.

The edge provided on the lower mold is 0 from the outer periphery of the medium-sized cavity.
．． 05~0.5mm preferably 0.05~OJmffl
In many cases, it is preferable that the tip of the edge be located at an outer position. The height of the edge tip may be the same as or slightly higher than the upper surface around the upper end of the cavity of the lower mold. The lower surface of the medium size facing this need only be flat.

If the amount by which the tip of the edge of the lower die is biased outward from the outer periphery of the medium-sized cavity is larger than the above range, the laminated film after molding will appear to be exposed, causing it to not reach the bottle opening. This is not preferable since there is a possibility that the adhesiveness during insertion and insertion may be impaired.

As the laminate film of the present invention, a fluororesin material can preferably be used from the viewpoint of gas permeability and chemical resistance. As such fluororesin, in particular, a flexible fluororesin composition (for example, the product name: Cepural Soft (manufactured by Central Glass Co., Ltd.) is preferable because it is stretchable, stable for pharmaceuticals, and can provide a highly productive pharmaceutical rubber stopper.

In the manufacturing method of the present invention, the gradual increase in pressure during molding is as follows:
For example, the mold may be tightened at a constant speed in about 3 to 10 seconds until the final pressing force (generally about 60 kg/cm') is reached.

[Example] The details of the present invention will be explained below based on the drawings.

FIG. 1 shows a cross-sectional view of the structure of the laminated rubber stopper 20 of the present invention. The periphery of the disc-shaped main body is a flange portion 20a, the lower surface of which is elastically attached to the upper surface of the bottle mouth (not shown). The laminate layer is not formed to allow close contact with the Further, reference numeral 20b represents a leg, and a laminate layer 21 of a film made of fluororesin is coated with a boundary line in the vicinity of the root portion extending to the flange portion 20a.

When the laminated rubber stopper of this example is manufactured by the manufacturing method described below, the boundary line at the upper end of the laminate layer 21 becomes the leg of the rubber stopper body and the road surface, as shown in the enlarged view of FIG. Since the laminate layer 21 has good adhesion to the inner surface of the bottle mouth, there is an advantage that it is possible to prevent the internal chemical solution from entering the bottle mouth side.

Next, a method for manufacturing the above-mentioned laminated rubber stopper will be explained.

First, the upper, middle, and lower molds of the mold are heated to the appropriate temperature for the rubber material.The mold used in this example has a cavity 38 that matches the shape of the legs, as shown in the exploded view in Figure 3. and a lower mold 3 having an edge 8 formed circumferentially upward on the upper end periphery of the cavity, and a cavity 2a that matches the outer peripheral shape of the root of the leg. It consists of a thin middle mold 2 that is used in combination, and an upper mold 1 that has a cavity 1a that matches the shape of the rubber stopper body and is used in combination on top of the middle mold 2.

Using the above mold, first, the fluororesin film 22 is placed on the lower mold 3 having a predetermined cavity and having an edge 8 formed around the upper end so that the adhesive-treated surface faces upward. Next, the middle mold 2 is placed on top of the mold 2, a sheet-like rubber material 10 is placed on top of the mold 2, and finally the upper mold 1 is placed on top of the mold 2, and this mold is put into a compression molding press and pressurized and heated. In most cases, the appropriate pressure is 40 to 60 kg/cn+' against the mold surface. After completion of molding and vulcanization, when the mold is pulled out from the press and the upper mold 1 is opened, the molded product is adhered to the upper mold 1. At this time, the cutting edge 8 already provided on the lower mold 3
The film 22 is cut between the molded product 20 and the lower surface 9 of the medium mold 2, and the fluororesin film 21 is completely integrated and laminated to the leg portion 20b of the molded product 20, and there is no need for finishing. The molded product is removed from the upper mold 1, the middle mold 2 is further removed, and the fluororesin film remaining on the lower mold 3 is removed. A punching device is used to cut the rubber strips connecting the molded products at the flange portions of the molded product 20, and the rubber plugs are separated into pharmaceutical rubber plugs 20 as shown in FIG.

[Effects of the Invention] Only the legs of the rubber stopper molded using the mold according to the present invention are suitably laminated with fluororesin to the necessary and sufficient extent, so elution from the rubber material is prevented and the chemical solution is The effect is that no pollution or foreign matter is observed. Further, since the molding can be completed in one step, it is economical, and has the effect that it is possible to supply a highly safe and inexpensive rubber stopper for pharmaceutical use, and the usefulness of the present invention is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an example of the laminated rubber stopper according to the present invention, Fig. 2 is a partially enlarged view of the same, Fig. 3 is a developed view of a mold for producing the same laminated rubber stopper, and Fig. 4 5 is a sectional view of the mold showing the state during molding, and FIG. 5 is an enlarged view of the same part. FIGS. 6(a) and 6(b) are longitudinal sectional views showing an example of a conventional laminate rubber stopper. 1... Upper mold, 20... Rubber stopper body, 2...
・Medium size, 20a...flange, 3...lower type,
20b...Legs, 8...Edges, 1...Fluororesin film. Figure 3 Figure 4 Series 1 Figure I Figure 2 Figure 5 Figure 6 (a)

Claims (1)

[Scope of Claims] 1. A rubber stopper for closing the bottle opening of a drug-enclosing bottle, which includes a disc-shaped main body having a flange that is tightly attached to the upper surface around the bottle opening, and a rubber stopper for closing the bottle opening of a drug-enclosing bottle. The leg has a leg that is inserted into the mouth, and a fluororesin film is laminated on the entire surface of the leg, with a circumferential boundary line in the vicinity of the base of the leg extending downward at a generally right angle from the bottom surface of the flange. Laminated rubber stopper. 2. A fluororesin film for lamination is placed on a lower mold with a cavity that roughly matches the shape of the leg, and a thin medium mold that has a cavity that matches the outer peripheral shape of the base of the leg is placed on top of the fluorine resin film described above. Place it on the resin film, place an appropriate amount of the rubber material forming the rubber stopper body in the cavity formed by the medium mold, cover with an upper mold having a cavity that matches the shape of the rubber stopper body, A method of molding a rubber stopper by pressurizing and heating, the method comprising: providing an edge for cutting a film around the upper end of the cavity of the lower mold, and gradually increasing the pressing force during the molding. manufacturing method. 3. A lower mold that has a cavity that roughly matches the shape of the leg of the rubber stopper and has an upward film cutting edge formed on the upper edge of the cavity, and a lower mold that matches the outer peripheral shape of the base of the leg of the rubber stopper. A thin middle mold, which has a cavity that matches the shape of the rubber body, is placed on top of the bottom mold, and an upper mold, which has a cavity that matches the shape of the rubber body, and is placed on top of the middle mold. A mold used for manufacturing a laminated rubber stopper, characterized by comprising a combination of the following.